1. Field of the Invention
The invention relates to a golf club, more particularly to a putter, and most particularly to a putter head and its attachment to the rest of the putter, that assists a golfer to meet the requirements and challenges of accurate putting.
2. Description of the Related Art
A golfer wants to sink the ball into the hole in as few shots as possible. A golfer""s goal, when putting, is typically to sink the ball with a single, and preferably straight, putt. Most golf clubs are used to drive the ball from the tee to the green. The putter is then used to stroke the ball into the hole in the green. In golf, the putter is the club where accuracy is more important than range, and its use accounts for some 40 percent of score, which is twice as much as the second most often used club, the driver. Good putting involves a complex mixture of static and dynamic aspects of human-factor, visualization, and structural/kinesthetic elements. A flaw of prior inventions in this field is that each addressed only a portion of what accurate putting requires.
xe2x80x98Shaftxe2x80x99 xe2x80x98headxe2x80x99 and xe2x80x98putterxe2x80x99 use the definitions stated by the USGA, Appendix II.
A putter includes a shaft with a gripping handle end and a head end. A putter head is fixedly attached to the head end of the shaft.
The xe2x80x98striking directionxe2x80x99 is a line parallel to the ground and identical to the initial straight line of the intended shot.
The xe2x80x98break pointxe2x80x99 is the point along the striking direction where either the ball goes in the hole, or the ground will force a change in the vector so ball will go in the hole, or at least come as close to the hole as is possible. After the putt reaches the break point, if it does not go in, the changes in the putt""s vector depend upon the external conditions, especially curvature, of the surface over which it travels.
The xe2x80x98strike vectorxe2x80x99 is that sub-part of the striking direction that extends from the golf ball to the break point; and its length is a critical as its direction.
The xe2x80x98X-Yxe2x80x99 plane is a two-dimensional plane where the X axis is parallel to the striking direction at the moment of impact between the putter and the golf ball and extends from the back to the front of the putter head, and the Y axis is perpendicular to the striking direction and extends from the left to the right of the putter head.
The xe2x80x98ground planexe2x80x99 is a two-dimensional plane with X and Y axes parallel to the ground where the X axis is parallel with, and the Y axis is perpendicular to, the striking direction. Generally, the X-Y and ground planes will be identical when putting.
The xe2x80x98strike planexe2x80x99 is a two-dimensional plane with Y and Z axes that is perpendicular to the ground plane and to the striking direction.
The xe2x80x98loft planexe2x80x99 is a two-dimensional plane with X and Z axes that is perpendicular to the ground plane and parallel to the striking direction.
The xe2x80x98striking facexe2x80x99 is the portion of the putter head that is designed to strike the golf ball. (Putters, under USGA rules, may have two strike faces, but only one may be operative for any given putt.) There may be both a theoretical striking face and an actual striking face; the former is perfectly parallel with the striking plane throughout the striking face and matches the golfer""s visualization of the putter, while the actual striking face will have a xe2x80x98strike linexe2x80x99 (a line on the striking face at the furthest forward point on the X axis, which extends along the Y axis) which is parallel with the striking plane, but otherwise be inclined from the theoretical striking face (i.e. deviate from a 90xc2x0 perpendicular to the ground plane), even though the degree of inclination may be imperceptible to the putter and not part of his visualization when putting.
The xe2x80x98rotational axis of the putterxe2x80x99 is the line extending from the putter shaft through the putter head. The shape of the parts actually connecting the shaft and the head may deviate from this line; it is the line of effect for rotation in the X-Y plane.
The xe2x80x98rotational center of balancexe2x80x99 is the point in the putter head where an equal torque in the X-Y plane will rotate the putter equally clockwise or counterclockwise.
The xe2x80x98rotational striking center of balancexe2x80x99 is the point in the strike plane on the line through the putter head that divides the mass of the putter head equally along the Y axis.
xe2x80x9cRotationally balancedxe2x80x9d means that a putter, when laid across the palm of the hand in such fashion that it does not tip down and with the strike face oriented parallel to the ground, remains in that position until disturbed, and will rotate clockwise and counterclockwise around the shaft (and thus, during a putt, in the ground plane) an equal degree for an equal amount of torque in the X-Y plane applied to either head or shaft.
xe2x80x98Stroke alignmentxe2x80x99 is alignment of the putter head with the striking direction such that the theoretical striking face matches the strike plane and is centered on the striking direction.
xe2x80x98Stroke triangulationxe2x80x99 is accurately measuring the strike vector, i.e. how far the putt will travel before reaching the break point (and as is desired in most cases, going into the hole).
xe2x80x98Stroke power estimationxe2x80x99 is deducing the power necessary yet only sufficient to cause the ball to traverse the strike vector, no more and no less.
xe2x80x98Strike alignmentxe2x80x99 is precision in the initial strike as to both alignment and power, such that the (dynamic) performance matches the (prior, static) visualization.
xe2x80x98Stroking alignmentxe2x80x99 is continued alignment of the motion of the center of the striking face along the striking direction during the follow-through.
Together, stroke alignment, stroke triangulation, stroke power estimation, strike alignment, and stroking alignment, determine a putt""s accuracy.
The xe2x80x98sweet spotxe2x80x99 means that area on a putter head""s striking face which should come into contact with a golf ball to give the optimal strike alignment and maximize kinesthetic feedback to the golfer (the latter also being known as xe2x80x98the best handling feelingxe2x80x99).
Successful Putting Requirements
The first and usually first-considered requirement in putting is that the golfer visualize the striking direction accurately. The best putt made, which was ill-aimed, is flawed. Even when conditions dictate that the ball, to go into the hole, must xe2x80x98breakxe2x80x99 from a straight line and follow the path dictated by those conditions [e.g. curving with the slope(s) of the green], the initial portion of virtually all strokes will be a straight shot along the strike vector.
Stroke alignment, which must precede each putt, requires a golfer to visualize a line from the center of the putter head that (1) is perpendicular to the theoretical striking face of the putter (a flat surface), (2) passes through the center of the golf ball (a spherical surface), and (3) passes through the break point (or hole). The design of a putter, particularly of a putter""s head, can greatly affect a putter""s ability to meet these requirements and challenges for accurate putting. Other patent applications for putter heads have used visual markings as the means for providing sighting aids to assist a golfer; most failed to consider, let alone use, the visualization properties of the putter head as a whole, and the rest only partially used the head""s structure and design.
Second and third, and subtler, requirements for any putt, that involve more expertise and skill, are that the golfer first correctly estimate the length of the strike vector, that is, the travel distance the putt must move along the striking direction to reach but not overshoot the break point, and then determine the correct power to put into that stroke. Stroke triangulation and stroke power estimation have been generally ignored by the prior art. Yet while inexperienced and moderately competent putters struggle with stroke alignment, more experienced and professional putters become far more concerned with stroke triangulation and stroke power estimation. Accurately estimating the distance between the ball and the break point involves two-dimensional visualization of the ground plane and translation of the three-dimensional cues concerning distance into a two-dimensional strike vector. Stroke power estimation requires accurately gauging the nature of the intervening surface (curved, wet, dry, thick, slick, slow, or fast) and the effect it will have on the stroke, which improves with experience only to the extent the putter provides proper feedback to the golfer from previous putts (successful or not).
Several inventions have addressed the first requirement by providing assistance for visualizing the striking direction. Most prior inventions focused solely on linear alignment. (U.S. Pat. No. 5,993,324, Gammil, A., identified other prior art featuring alignment aids.) The most common approach was perpendicular squaring, and the more effective art, that of multiple, parallel squaring. These are different approaches to xe2x80x98perspective boxingxe2x80x99 (forming multiple parallel lines which will fall on either side of the striking vector and pass on either side of the hole); but Gammil""s approach, like those cited therein, all fail to provide means to address the second and third requirements. As any putter knows who has watched his putts fall short of, or bounce over, the hole, alignment may be necessary, but it is not sufficient for truly accurate putting.
After visualizing the putt (the static aspect of the skill), the golfer must perform the putt (the dynamic aspect of the skill). The putter is swung back, forward to impact the ball, and then through the ball""s initial position; these are the backswing, foreswing, and follow-through. Each must be properly performed for a perfect putt.
The fourth requirement for an accurate putt therefore is that the putter strike the ball correctly, which involves a number of included sub-requirements. The golfer must visualize and produce, dynamically, the precise, and preferably perpendicular, tangent between the spherical form of the ball and theoretical striking face at the moment of impact. For all but the shortest of strokes, the break point will be out of the golfer""s sight picture at that moment (golfers look at the ball, not at the break point, when they are putting). As multiple parallel lines extend into infinity without changing, estimating distance at that moment is an unsolved dilemma in the prior art. A golfer must focus, but not fixate, on the strike; too tight a grip, or too over controlled a swing, are just as bad as too loose a grip or uncaring a swing. The initial strike must be precise both in the alignment of the striking surface of the putter head as it encounters the ball, so the ball will not move across the putting green at an unintended angle or with a surprise hop or skid, and in its power, so the ball will neither undershoot nor overshoot the hole. The swing must align with the striking direction to avoid unintended spin, and with the ground plane to avoid fouling the ground or causing undesired loft, top-spin, or backspin, which will interfere with the ball""s travel along the strike vector.
Two of the most common problems in strike (and stroking) alignment arise from minute, unintended or unperceived rotations of the striking face in the ground plane. If the rotation is clockwise (from a viewpoint looking down at the ground, for a right-handed golfer), the ball will veer off to the right (or xe2x80x98slicexe2x80x99); if the rotation is counterclockwise, the ball will veer off to the left (or xe2x80x98hookxe2x80x99). Stroke alignment requires a distant and static perspective which includes the both the xe2x80x98start pointxe2x80x99 and the xe2x80x98end pointxe2x80x99 of the intended line; but strike alignment requires a near and dynamic perspective, which concentrates on the xe2x80x98start pointxe2x80x99 where the impact occurs; while stroking alignment shifts back to a distant yet dynamic perspective which includes the break point. Prior art fails to consider that a putter head""s design should and could support each of these differing needs.
Other common problems with strike and stroking alignment include (1) moving the putter head along the Y axis while striking through the X axis, which can put undesired spin or xe2x80x98Englishxe2x80x99 on the ball when it is struck; (2) moving the putter head through the loft plane such that it contacts the ground and fouls strike or stroking alignment; or, (3) moving the putter head through the loft plane unnecessarily, dampening kinesthetic feedback. Any twist in the putter head in the X-Y plane during the swing (back, fore, and follow-through) creates torque and inclines the striking face from the perpendicular to the striking vector. Any of these will create an off-line shot, that is, one which will deviate from the striking vector. In addition, if the putter strikes the ball on either side of the rotational striking center of balance, the putt creates torque when the striking face hits the golf ball, which will tend to twist the putter head from the perpendicular and thus impart an off-line shot. All of these are problems of strike alignment during the backswing and foreswing, and stroking alignment during the follow-through.
Stroke alignment, strike alignment, and stroking alignment must be identical for the shot to be accurate. They will not sufficexe2x80x94the length of the putt, the stroke power, is also criticalxe2x80x94but if they differ, the putt must go wrong. Matching performance to visualization (generally) improves with experience, especially if the putter provides good feedback that permits the golfer""s kinesthetic sense to match which his visualization.
(Positive emotional feedback, while desirable and intended, is beyond any guaranteed reach of this application. The most choosy and perfectionist golfers can never be satisfied. The applicant cannot and does not promise that putting better will make any golfer happier, richer, or more admired.)
Developing the experience and awareness of the proper feel for each putt, maximizing the positive kinesthetic feedback from each putt, is one of the challenges and delights in golf. It is well understood in the sport that the xe2x80x9cfeelxe2x80x9d of a club as transmitted to the golfer""s hands is important for control and accuracy. Various patents and applications have considered different materials, different masses, or different mass distributions, yet have not considered a design approach for the clubhead which promotes such feel irrespective of the material, mass, or distribution by differentiating the response during strike alignment and stroking alignment, or by structure that promotes resonance keyed to human factors and expectations.
Golfers rarely intend for putts to have any motion in the loft plane; they want to avoid having the putter head contact the ground during the putt, including the follow-through, as this generally spoils the stroke.
In conventional and prior designs, the mass of the head is so distributed that the sweet spot is not as wide as the striking face, which makes it more difficult for golfers to make the sweet spot contact the ball. Missing the sweet spot usually causes the ball to travel a considerably lesser distance, and often contributes to the tendency to xe2x80x9cpushxe2x80x9d or xe2x80x9cpullxe2x80x9d the ball (to the right or left, respectively); or, in other words, to create problems with both stroke and stroking alignment. It also decreases the kinesthetic feedback from that putt.
Techniques to broaden the sweet spot generally provide a means to concentrate the weight of the club head in the heel and the toe rather than directly behind the sweet spot. In one particular design, the head is fabricated of a relatively light material and inserts of denser material are provided in the area of the heel and toe of the club head. In another design, the portion of the club head directly behind the club""s ball-striking face is removed so that the weight is necessarily located in other portions of the head, namely the toe and heel portions. While in both of these designs the sweet spot is indeed broadened, they disturb strike alignment as the striking face of each of these clubs lacks the stiffness needed to advantageously utilize the elastic energy generated in the golf ball. This stiffness is needed in order to preclude any deformation of the face, under impact, that would tend to increase the area of contact between the face of the ball and thus dissipate energy in the club head instead of imparting it to the ball. Moreover, they disturb stroking alignment to the extent that they cause problems with rotational striking center of balance, and thus the effective sweet spot, if not done correctly. Distribution of the mass alone fails to consider the interactions between and amongst the different elements of the putter head, which interaction ineluctably becomes part of the feedback. Furthermore, such distortions do not provide resonance. While golfers have long talked about the xe2x80x98feelxe2x80x99 of a club, prior inventions have paid little attention to engineering designed to improve that aspect. The golfing world and even several patents may have discussed xe2x80x98the sweet spotxe2x80x99 of a putter, but the prior art does not include design aspects which deliberately foster a better sweet spot for a given amount of mass by focusing on the interaction between and amongst subordinate elements of the putter head.
The fifth requirement for an accurate putt is that the putter continue to move along the correct striking line for the short period after the initial strike when the ball may re-encounter the putter, and at least during that (preferably short) period when the ball is in contact with the putter. The ability to produce the right direction and amount of xe2x80x98follow throughxe2x80x99 depends upon proper feel for both the putter and the moment of contact during the stroke. Thus, a golfer must perform xe2x80x98stroking alignmentxe2x80x99, during the follow-through phase immediately after the moment of initial contact, for each putt. If the stroke does not follow the strike line, the putter may impart unintentional spin or xe2x80x98Englishxe2x80x99 to the ball, which will throw a curve into the planned shot.
Designing a putter to meet all of the above requirements, while staying within the formal USGA and xe2x80x98match playxe2x80x99 restrictions, has led to a fair amount of prior art. Most of these inventions, however, focus on only one of the above requirements and thus fail to meet the advances taught in the present invention.
Prior Art Teachings and Differences
In U.S. Pat. No. 4,227,694, Drake, R., an xe2x80x98aim-assistingxe2x80x99 linear element is included as an element on the shaft, which throws off the rotational center of balance for the putter.
U.S. Pat. No. 4,253,667, Clark et. al., attempts to provide a better xe2x80x98sweet spotxe2x80x99 by using an H-shaped design to spread it laterally; but fails to consider elements essential to strike alignment, resonance, and stroking alignment; in fact, that invention""s convex bottom shape makes stroking alignment more rather than less difficult, since the purpose of that element is to make the same putter work equally well for different players.
U.S. Pat. No. 4,265,451, Bernhardt, F., uses another xe2x80x98sighting linexe2x80x99 approach that modifies the shaft by including a weighted neck member, without regard to its negative effects on the striking and stroking alignment, feedback, or sweet spot.
U.S. Pat. No. 4,369,974, Komperda, J., teaches the use of transparent or translucent material to provide internal sighting lines, and considers the concept of parallel lines to xe2x80x98matchxe2x80x99 the striking direction, but provides no means for ready estimation of the distance of the striking vector.
U.S. Pat. No. 5,209,474, Voyer, P. teaches the use of an elongated shaft; U.S. Pat. No. 5,595,385, Jablonski, T. teaches use of a multi-sectional shaft with a anti-rotational handle (a design which violates the restrictions in the USGA rules); and U.S. Pat. No. 5,632,691, Hannon, et. al. Teach specific design limitations to the shaft; none of these address putter head design.
U.S. Pat. No. 5,993,324, Gammil, A. evaluates much of the prior art concerning strike alignment, and produces a design which addressed issues therein as well as providing means for customization. (USGA rules specifically prohibit modification of a club during a round, limiting the desirability of this feature.) This patent is discussed in further detail below, as there are other aspects where the present invention differs significantly that were unaddressed, or inapt, in Gammil""s work.
U.S. Pat. No. 6,190,266, Pamias, F. and the many patents cited therein, also relate to the design of the shaft(s) or handle(s) of a golf putter; the former does state a specific set of principles governing their attachment to the putter head, but otherwise these do not address putter head design.
U.S. Pat. No. 6,200,226, Regan, K., integrates a ball mark assembly in the putter head; U.S. Pat. No. 6,234,915, Wu, K. requires an anti-shock slat or neck; and U.S. Pat. No. 6,244,974, Hanberry, Jr., E., requires obtuse angles and quintuple faces on the putter head, all elements missing from and irrelevant to the present invention.
U.S. Pat. No. 6,200,227, Sery, J., does not include means for stroke alignment, strike alignment, and striking alignment, nor address dynamic as well as static concerns with accurate putting. Additionally, that patent is designed to position the golfer""s head and eyes to a particular fixed point, above the center of gravity of the putter, rather than improving the putt independent of the plane of position of the golfer""s head.
U.S. Pat. No. 6,203,443, Britton, R. least considered the problem that visual markings on a putter, particularly on the club head, fail in themselves to provide proper sight lines, as they are not perpendicular to the face of the putter but only perpendicular to a vertical plane. However, that invention used variable loft or variable weight as the means to address this problem. Also, providing sighting aids to achieve correct alignment and optimum aim addresses only the problem of stroke alignment, and thus this patent did not address the problems of striking and stroking alignment. That patent conceded that using lines alone is unsatisfactory, xe2x80x9cBecause these sight lines too are generally not perpendicular to the striking face, the golfer has two parallel sets of sight lines to look at, neither of which are perpendicular to the striking face.xe2x80x9d
U.S. Pat. No. 6,203,445, Rhodes, B. et. al., also considered only the element of stroke alignment and incorporated a second alignment face in the head, an element not required in the present invention.
U.S. Pat. No. 6,213,890, Prince, R., hypothesized that the area of the xe2x80x9csweet spotxe2x80x9d is directly proportional to the mass of the head of the instant putter, then used a crude approach of simply increasing the mass of the head. (In engineering, this common and simplistic approach to a solution is known as xe2x80x98using a bigger hammerxe2x80x99.) Though the invention discusses some physical principles, and a good amount of the prior art, it failed to consider further application of engineering to attain superior performance for a given or equal mass by intelligent distribution and interconnection of sub-elements.
U.S. Pat. No. 6,251,027, Buchanan, D., teaches a different design to the shaft to improve the xe2x80x98feelxe2x80x99 of the putter. And U.S. Pat. No. 6,234,915, Wu, K. teaches the use of an anti-shock slat in the neck. Both incorporate elements not needed in and irrelevant to the present invention.
U.S. Pat. No. 6,244,974, Hanberry, E., returns to the sighting alignment problem with by providing a plurality of azimuthal sighting lines and multiple faces to the putter, pressing dangerously close to violating the USGA rules thereby. All that is taught, however, is xe2x80x98sighting linesxe2x80x99; none of the problems of stroke triangulation, striking alignment, or stroking alignment are addressed.
U.S. Pat. No. 6,251,026, Bonvillain, J., modifies the shaft to allow for not just one, not just two, but three possible sighting alignment means, leading to speculation as to which problem the inventor considered to be his worst . . . and including multiple elements neither necessary nor relevant to the present invention.
U.S. Pat. No. 6,261,190, Ashcraft, D. teaches sight alignment means which use separation of an embedded alignment figure to indicate disorientation . . . without, however, including means to produce the initial, correct alignment with the striking direction. That, one supposes, just happens fortuitously or through the skill of the golfer.
U.S. Pat. No. 6,264,571 teaches means to dynamically balance a putter by modifying the alignment between the putter head and shaft through a sliding hosel, an element not used and a concern not addressed in the current invention.
U.S. Pat. No. 6,267,689, Ambrose, J. teaches modification of the putter head to redistribute the center of mass thereof and uses a generally triangular shape to the whole head, without considering the concerns of stroke triangulation, striking alignment and striking alignment, although it uses the shaft to control aspects of the problem of stroke alignment. However, the core of this invention is the concentration of the putter head mass in the upper half, mass differentiation along the vertical plane, which is not an element nor a concern of the present invention.
U.S. Pat. No. 6,267,690, Salmon, M. teaches a reasonable method to improve the putt by incorporating a curved configuration to the striking face, which unfortunately violates the USGA rule requirement that the club face xe2x80x9cshall not have any degree of concavityxe2x80x9d. Moreover, the design of that invention is intended to impart spin or backspin to the ball, one of the problems the current invention seeks to obviate or correct.
U.S. Pat. No. 6,270,422, Fisher, D. incorporates a trailing member, or trailing members, but does so irregardless of the effect on either the stroking alignment or the dynamics of the sweet spot. And, while that invention teaches that the trailing member may be a triangle, the considerations of the fit, spacing, alignment and connection between the trailing member(s) and the striking element that assist with the stroke alignment (particularly the distance element), striking alignment, and stroking alignment are not taught nor disclosed, let alone discussed therein. That inventor, however, did state correctly that xe2x80x9ca large polar moment of inertia is desirable because it resists any tendency of a golfer to twist the club shaft as it is swung forward to impact a ballxe2x80x9d, thereby at least recognizing one aspect of the problem of striking alignment. The patents disclosed therein, and incorporated by reference herewith, did not, as Fisher points out, address the striking alignment problem. The chief purpose of Fisher""s teaching, however, was to balance the heel-and-toe elements of the polar inertia by use of the trailing member(s), which problem the present invention solves in a different and simpler fashion, without requiring differential or adjustable weighting. Also, while Fisher talks of xe2x80x98framing linesxe2x80x99 for the stroke alignment problem, he fails to consider means to create more than mere polar inertia resistance.
Many other patents address elements, aspects, or concerns which are disparate from the present invention. In U.S. Pat. No. 6,273,827, Hockerson, S. teaches use of a resilient ball-striking pad on the striking element, an aspect and element not considered nor used in the present invention. U.S. Pat. No. 6,280,346, Gedeon, R. teaches the use of a mallet head, and focuses on the design of shaft, grip, and their interconnections, which are also not relevant to the present invention. And in U.S. Pat. No. 6,283,874, Studebaker, J. focuses on shaft design, a concern distinct from any aspect of the present invention. Finally, in U.S. Pat. No. 6,283,875, Jones, D. teaches the use of a support implement using paired leg members to stand a club up. All of these include concerns, elements, and aspects neither necessary nor relevant to the present invention.
By connecting the shaft such that the rotational axis of the putter passes through the rotational striking center of balance, distributing the mass of the putter head outward from the rotational center of balance and with a rearward bias along the X axis, incorporating sub-elements of the putter head that enable parallel and reflexive triangulation, using energy-reflective and transmissive connections amongst the sub-elements, and shaping each sub-element and their combination in accordance with human-factor visualization, focusing, and kinesthetic principles, an improved golf putter is created that enhances the golfer""s ability to perform stroke alignment, stroke triangulation, stroke power estimation, striking alignment, and stroking alignment, and thereby to putt better.